BigInteger to Byte Array Little Endian Unsigned - Java java.math

Java examples for java.math:BigInteger

Description

BigInteger to Byte Array Little Endian Unsigned

Demo Code

/**/*from  www.j  a v a  2  s. co  m*/
 *     Copyright (c) 2013, Will Szumski
 *
 *     This file is part of formicidae.
 *
 *     formicidae is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     formicidae is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with formicidae.  If not, see <http://www.gnu.org/licenses/>.
 */
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.Arrays;

public class Main{
    public static void main(String[] argv) throws Exception{
        BigInteger bi = new BigInteger("1234");
        System.out.println(java.util.Arrays.toString(toByteArrayLittleEndianUnsigned(bi)));
    }
    public static byte[] toByteArrayLittleEndianUnsigned(BigInteger bi) {
        byte[] extractedBytes = toByteArrayUnsigned(bi);
        byte[] reversed = ByteUtils.reverseArray(extractedBytes);
        return reversed;
    }
    public static byte[] toByteArrayUnsigned(BigInteger bi) {
        byte[] extractedBytes = bi.toByteArray();
        int skipped = 0;
        boolean skip = true;
        for (byte b : extractedBytes) {
            boolean signByte = b == (byte) 0x00;
            if (skip && signByte) {
                skipped++;
                continue;
            } else if (skip) {
                skip = false;
            }
        }
        extractedBytes = Arrays.copyOfRange(extractedBytes, skipped,
                extractedBytes.length);
        return extractedBytes;
    }
}

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